Lewis & Short

Tătĭus, ii, m., T., a king of the Sabines, who afterwards reigned jointly with Romulus, Enn. ap. Prisc. p. 947 P. (Ann. v. 113 Vahl.); Cic. Rep. 2, 7, 13; Liv. 1, 10 sq.; Prop. 4 (5), 2, 52.
Hence,

    1. 1. Tătĭus, a, um, adj., of Tatius: turma, Prop. 4, 4, 31.
    2. 2. Tătĭenses (sometimes also called, after his praenomen Titus, Titienses), ĭum, m., one of the three Roman centuries of cavalry, Varr. L. L. 5, 9, 17; Cic. Rep. 2, 20, 36; Liv. 1, 13; Aur. Vict. Vir. Ill. 2; Ov. F. 3, 131.